16 replies to this topic

[mhtelescoper]

I've started down the Astrophotography rabbit hole.  I'm improving, but still relatively new.

 

Here is my setup:

 

Celestron C11 with CGEM (original, not the II)

ASIAir Plus

Canon EOS R

Starizona Corrector IV (.63)

ZWO OAG-L with ZWO ASI290 Mini

 

For focusing, I use a bahtinov mask and feel like I've had pretty good success with it.  

 

I'm wondering if adding the ZWO EAF would be worth it.

 

Thanks,

-Matt

[hyiger]

I have it on both scopes (C11 and WO GT81) and in combination with the ASIAir+ it's definitely worth it. If you are doing long sessions it's handy to have it auto-refocus due to temp changes for example. I also keep a log of focuser positions with various setups and with that I can quickly goto to a reasonably close focus when I change my image train; then use the AAP autofocus to then get a precise focus. With the C11, even with a feather touch manual focuser it was difficult for me to get precise focus or to remember to refocus later. Plus when it gets cold I can sit inside and focus. 

Edited by hyiger, 04 September 2022 - 04:03 PM.

[Jim Waters]

I have 2 and have had no problems with them.

[dave85374]

It doesn't take much time to put on or take off a Bahtinov mask off my camera so I think the added money for the ZWO EAF probably wouldn't be worth the money.

[rgsalinger]

With an EAF in place, you just let your imaging software autofocus as necessary. Necessary can mean when temperature changes, after a certain amount of time, when you change filters, when the mount flips, etc. It all depends on your software. Without that, you have no way of knowing (other than staying up all night and monitoring the system) when to refocus. 

 

The OP has maybe 10K invested in their system so to me investing another two hundred or so to be able to run unattended all night seems obviously "worth it". FWIW, I have one of these on my 4" refractor and it works much better than I ever would have expected a 200 buck focuser to work. Excellent product, IMHO.

 

Rgrds-Ross

[jlinsobe]

Absolutely.  

Just remember to order the appropriate bracket-kit for your own scope.

They are quite reasonably priced.

 

Get the newest version though, 5v

[zakry3323]

They're great, and the new 5v version means that you don't have to deal with an additional power supply- it gets all the juice it needs from its USB connection.

Not really EAF-specific, just autofocus in general: there is no guessing involved- you'll go from feeling like you've had pretty good success to KNOWING that you're getting the sharpest focus possible for all of your subs all night, night after night. 

 

Once you try it, I'll bet your baht mask becomes your new frisbee! 

[hyiger]

They're great, and the new 5v version means that you don't have to deal with an additional power supply- it gets all the juice it needs from its USB connection.

Not really EAF-specific, just autofocus in general: there is no guessing involved- you'll go from feeling like you've had pretty good success to KNOWING that you're getting the sharpest focus possible for all of your subs all night, night after night. 

 

Once you try it, I'll bet your baht mask becomes your new frisbee! 

My dog loves her new Bahtinov mask toy. 

[KevinFH]

My take is that when you do narrow band imaging, then you need EAF.

The ZWO EAF works well; I have used it on four completely different setups without a hitch.

For a color camera, EAF isn't as critical.  Yes, temperature affects can be an issue for some setups.

I used to check my focus regularly when using a color camera; throwing a Bhatinov mask up there momentarily is not hard.

 

Each filter used requires refocus.  Many nights I have all 7 filters programmed to be used.  EAF makes this easy (so I can go to bed).

No filter is in so long that temperature changes are an issue.

 

I don't disagree with the statements above about how accurate the EAF seems to be: always pinpoint stars.

 

Now that I have EAF on my mono setups, I would use it on my color camera setup (Nikon) if it ever goes on the scope again.

[GR-Amateur]

I nowadays use EAF with a dslr but before I purchased it I asked my self the same question*… Now I know... It totally worths it.

(*Am I just buying another fancy gadget to play with? I do not want to become that guy…)

Bahtinov mask and manual focusing can be very accurate but you have to mess around with the mount a lot to point at a bright star and loose precious time, stop session pause guiding, change target framing, plate solve, start all over session …etc)

During a session, I might refocus 4-5 times or even more when temperature rapidly drops. (Btw EAF’s thermometer is very handy)

Also,
Among other by keeping a focusing log per filter,
I have discovered many times technical problems in my imaging train, as well learned many things about sky conditions by validating focusing reading (ex.inv power o hfd readings during focusing etc at certain stars).

[erictheastrojunkie]

In terms of automation and ease of running an astro rig the autofocuser is probably the single biggest game changer in terms of "non-critical" equipment. Of all the peripheral accessories I've added to my setups over the years the EAF's have made the biggest difference in terms of quality of life for imaging. Not having to sit at the scope/lens and focus with tiny adjustments back and forth and not having to worry about focus drift from the start of the session to the end is a game changer. If you have the funds then definitely get the EAF or another autofocuser. 

[astrohamp]

The EAF made a huge difference running a large refractor/GEM visually as well.  No settling time required after a focus attempt.  Parafocal EPs help as well either by design or by connected adapters. 

 

An essential nice-to-have for EAA observing for me as well.

[Jrpavlock]

It doesn't take much time to put on or take off a Bahtinov mask off my camera so I think the added money for the ZWO EAF probably wouldn't be worth the money.

[Jrpavlock]

Unless you don't feel like getting up in the middle of the night several times to use the mask. 🤷‍♂️

[AndyMcKay]

It doesn't take much time to put on or take off a Bahtinov mask off my camera so I think the added money for the ZWO EAF probably wouldn't be worth the money.

It's not the initial focus that's the benefit, it's the re-focusing over night to ensure that focus hasn't drifted due to temperature changes, etc.

[CharLakeAstro]

I started with (1) EAF, and now have (3). Because I didn't want to move it from scope to scope to scope.

Totally worth the spend.

[dhferguson]

Cheers,

 

Post #11 has it right: an EAF or other autofocuser is indeed a game changer. It means you can sleep all night long instead of staying up to adjust focus. In the case of my former setup, a C8 Edge, such an adjustment was required every 2 deg F minimum all night long as the temperature dropped. I found the EAF worked great with N.I.N.A.

 

Happy observing always,

 

Don